<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>在这里进行练手</title>
</head>
<body>
    
</body>
<script>
    console.log('数字:', typeof 1);
    console.log('字符串:', typeof '1')
    console.log('undefined:', typeof undefined)
    console.log('null:', typeof null)
    console.log('function:', typeof String)
    // console.log('')
</script>
</html>